The Prairie Pothole Region (PPR) is one of the most important areas on the continent for grassland-nesting birds. For example, this region alone is responsible for producing more than half of the North American population of dabbling ducks—an ecologically-, culturally-, and economically-valuable guild of birds—. The PPR in northwestern North Dakota coincides with the Bakken shale formation, where rapidly accelerating oil and gas development has the potential to impact millions of breeding waterfowl pairs. While oil and gas development has negatively affected other ground-nesting birds such as sagebrush passerines and greater sage-grouse in Wyoming, the potential impact on breeding waterfowl in the PPR is unknown. In addition, the PPR landscape is already heavily fragmented by agriculture, and increasing land conversion and disturbance from petroleum extraction may further exacerbate deleterious effects. The availability and quality of upland nesting habitat directly influences duck nest density and success, which have been shown to ultimately drive waterfowl populations. In this study, we located and monitored waterfowl nests in survey plots that were stratified by intensity of energy development as measured by the number of well pads present within the approximate home range of breeding waterfowl.
Results/Conclusions
Over three years, we systematically searched 8,657 hectares of grassland and monitored 4,777 duck nests. Blue-winged Teal (Anas discors), Mallard (Anas platyrhynchos), and Gadwall (Anas strepera) comprised 75% of nests that were located each year. We used program MARK to build models of nest survival based on ecological variables measured at local and landscape scales, as well as various metrics of oil and gas activity. In 2015 and 2017, we observed a weak increase in nest survival with an increase in the intensity of petroleum development. One possible explanation for this unexpected trend is that oil and gas activity had a strongly negative impact on nest predator populations (through traffic mortality or by inducing disturbance avoidance), which in turn bolstered waterfowl nest survival. In 2016, we observed no effect of extractive activity on nest survival; this period coincided with an economic downturn in oil and gas prices and concomitant reductions in active pumping and reduced road traffic. Our results contribute to our understanding of an increasingly common anthropogenic threat to ecological systems, and suggest that oil and gas activity can have complex effects on trophic webs in prairie grassland ecosystems.